Ultrasonic level transmitters are non-contact measurement devices that use sound waves to determine the level of liquids and solids. They provide reliable measurement in tanks, silos, and open areas. Compared to radar, capacitive, or hydrostatic methods, they are often more cost-effective and easier to install, making them highly popular across industries.
WORKING PRINCIPLE
The sensor emits ultrasonic pulses toward the material surface. The time taken for the waves to return is measured, and the distance is calculated to determine the level.
Basic formula: d = (c × t) / 2
Where:
d: distance (m)
c: speed of sound (343 m/s in air)
t: round-trip time (s)
The difference between tank height and this distance gives the material level.
STRUCTURAL FEATURES
- Measuring range: 0.2 m – 70 m
- Body materials: PVDF, stainless steel, PP
- Output signals: 4-20 mA, HART, Modbus, Profibus
- Protection class: IP67 – IP68
- ATEX and IECEx certified models
ADVANTAGES AND LIMITATIONS
Advantages:
- Non-contact measurement, no corrosion risk
- Easy installation and minimal maintenance
- Suitable for dusty and aggressive environments
- Flexible for various tank geometries
Limitations:
- Foam and vapor can affect measurement accuracy
- Narrow tanks may cause reflection issues
- Temperature fluctuations influence sound velocity
SELECTION CRITERIA
- Tank height and geometry
- Physical properties of the measured medium
- Environmental conditions (temperature, pressure, humidity)
- Communication protocols
- Explosion-proof certifications (ATEX, IECEx)
APPLICATION AREAS
- Water and wastewater treatment plants
- Food and beverage industry
- Chemical industry (corrosive liquid storage)
- Cement and mining (solid storage silos)
- Power plants (ash, coal, and liquid tanks)
STANDARDS
- IEC 61010 (safety for measurement devices)
- ATEX & IECEx certifications
- NAMUR NE 107 (diagnostic status)
CONCLUSION
Ultrasonic level transmitters are widely used in industrial facilities due to their non-contact measurement advantages and durability. Proper selection and installation help reduce operating costs while increasing process reliability.